The technical portion of an optician's profession consists in mounting a pair of ophthalmic lenses in or on the frame selected by the wearer, in such a manner that each lens is properly positioned relative to the corresponding eye of the wearer so as to perform as well as possible the optical function for which it is designed.
In order to mount a pair of ophthalmic lenses, the optician or operator needs in particular to proceed with shaping each of the lenses on the basis of optical, geometrical, and morphological order data. Shaping a lens consists in modifying the outline of the lens so that it fits the selected frame and/or the desired lens shape.
In order to perform such shaping, it is necessary to perform a certain number of operations using a lens-preparation device. Known lens-preparation devices comprise firstly a computer on which recording software is installed for recording lens order data, and secondly a set of treatment appliances for treating lenses including amongst others an appliance for centering lenses and a shaper machine.
The geometrical order data includes the shape desired for the lens after shaping. The desired shape is defined digitally using an appliance specially designed for reading the internal outline of the rim of the frame or the outline of a lens template, or indeed an electronic file that has been prerecorded or supplied by the manufacturer. This shape information is recorded in turn in the recording software.
After selecting the frame, the operator needs to situate the position of each eye in the frame of reference of the frame. The operator places the frame selected by the wearer on the wearer's nose and takes several measurements. These measurements provide data relating to the morphology of the wearer. The operator thus determines mainly two parameters known as centering parameters associated with the morphology of the wearer, specifically the pupillary distance and also the pupil height relative to the frame. The operator inputs this morphological mounting information by using the recording software.
When ordering a pair of lenses (also referred to as a “job”) associated with the wearer, the operator uses the recording software to input appropriate order data, i.e. the optical order data for the two lenses of the future pair. This includes in particular spherical and cylindrical powers, prismatic axes, and where appropriate power addition.
When the operator receives a pair of lenses for which order data has already been recorded in the order data recording software, each appliance in the set of treatment appliances needs to be informed which received pair of lenses is to be treated so that it can recover the recorded order data for the lens that is to be treated.
For this purpose, the order data recording software can print out a sheet summarizing the main elements of the order (customer name, optical characteristics of the prescription, etc. . . . ) together with a bar code for identifying the pair of lenses. After preparing an order for a pair of lenses, the operator places the frame and the sheet provided with the identification bar code for that pair of lenses in a tray, while waiting to receive the pair of lenses that has been ordered.
On receiving the pair of lenses to be treated the operator uses a bar code reader associated with the centering appliance to read the bar code on the printed sheet. This operation then enables the order data essential for centering the lens to be recovered, i.e. essential for causing the geometrical frame of reference of the lens to coincide with the position of the pupil so that the characteristic points and directions are properly positioned in the frame. Thereafter, the operator blocks the lens by placing a sticky gripper accessory thereon to mark physically the center of the frame of reference of the lens.
Thereafter, the operator reads the bar code of the printed sheet using a bar code reader associated with the shaper machine so that the computer can deliver to that machine the geometrical data representative of the shape of the outline for each of the right and left lenses.
Such a configuration requires the operator to perform handling that is awkward since the operator must first identify the sheet that corresponds to the order for the pair of lenses that has been received, and must then scan the bar code of the printed sheet in order to be able to select said pair of lenses (or job) and enable the treatment appliance in question to receive the order data corresponding to the selected pair of lenses. Such manipulation is time consuming and can be a source of errors. In particular, during shaping, the operator might well interchange the left and right lenses. The operator also depends on the tray without which the lens cannot be identified, and confusion can arise in particular between two lenses or two jobs. It can thus happen that the operator selects a blocking accessory that is not suitable for the lens that is to be shaped.
The above solution requires bar code reader means, thereby increasing the cost of the device for treating the pair of lenses. Furthermore, the use of printed identification sheets that can be read by the operator prevents the treatment of the lenses being automated.